JP5044999B2 - Perfluoroelastomer composition and perfluororubber molded article - Google Patents

Description

The present invention relates to a perfluororubber molded article having excellent compression set characteristics and a perfluoroelastomer composition used for the production thereof.

As fluororubbers, vinylidene fluoride / hexafluoropropylene copolymers, tetrafluoroethylene / propylene copolymers, tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymers, and the like are known.
Among these, tetrafluoroethylene / perfluoro (alkyl vinyl ether) copolymers are called perfluoroelastomers, and are extremely excellent in heat resistance, chemical resistance, and plasma resistance.

As a method for crosslinking a perfluoroelastomer, a method is known in which a perfluoroelastomer containing an iodine atom, a bromine atom or the like is peroxide-crosslinked (see, for example, Patent Document 1). Of these, iodine-containing perfluoroelastomers are widely used because they have a short crosslinking time and it is not necessary to add a metal oxide for crosslinking.

As a method for producing an iodine-containing perfluoroelastomer, a general formula RI ₂ (wherein R is a saturated fluorohydrocarbon group having 1 to 16 carbon atoms, a chlorofluorohydrocarbon group, or a hydrocarbon group having 1 to 3 carbon atoms) There is a method of producing a perfluoroelastomer having an iodine atom at a polymer terminal by copolymerizing a perfluoromonomer in the presence of a diiodo compound represented by (for example, see Patent Document 1). However, the perfluoroelastomer produced by the above method tends to be scorched when the iodine content is adjusted to a necessary crosslinking density as a rubber so that the iodine content is excessive and the crosslinking proceeds rapidly. On the other hand, when the iodine content is reduced to an amount that does not scorch, there is a problem that the crosslink density is low and the rubber properties are inferior.

  The rubber molded product obtained by crosslinking the perfluoroelastomer produced by the above method is a molded product of other fluororubber such as vinylidene fluoride / hexafluoropropylene copolymer or tetrafluoroethylene / propylene copolymer. Compared to the above, there was a drawback that the tensile strength at break was low. In particular, when perfluoroelastomer is used as a sealing material for a semiconductor manufacturing apparatus, there is a demand for minimizing the amount of compound used when molding rubber. For example, carbon black, which is widely used as a rubber reinforcing agent, is a source of dust generation from the sealing material, and there has been a demand for reducing the compounding amount. However, if the blending amount of carbon black as a reinforcing agent is reduced, there is a problem that the tensile strength of the perfluoroelastomer molded product is significantly lowered.

For this reason, the iodine content of the polymer terminal is lowered, and CF ₂ = CF—R ^f1 —X (wherein R ^f1 is a saturated polyfluoroalkylene group or a polyfluorooxyalkylene group, and X is I or Br. There is reported a method of adjusting the crosslinking density by copolymerizing an iodine or bromine-containing monomer represented by (for example, see Patent Documents 1 and 2).
When the crosslinking density is increased by this method, other important physical properties, such as tensile breaking elongation and compression set, may be deteriorated.

A perfluoroelastomer composition that is easy to knead, has a sufficiently high tensile strength, and gives a perfluororubber molded article having excellent tensile elongation at break and compression set is not known.
Addition of quinones and phenols as scorch retarders for the purpose of adjusting the crosslinking reaction rate in the crosslinking process of elastomers is known for hydrocarbon rubbers and non-perfluoro fluorine-containing rubbers (for example, Patent Document 3). 4).

However, it is not known to add a scorch retarder during peroxide crosslinking of perfluoroelastomer, and as an effect, it is completely known that in addition to preventing scorch, the physical properties of the resulting molded product can be improved. It is not done.
Under such circumstances, the perfluoroelastomer is excellent in processability, difficult to scorch, and a perfluoro rubber molded product obtained by crosslinking is excellent in rubber properties such as tensile strength and tensile elongation at break and compression set properties. A composition was sought.

Japanese Patent No. 3508136 Japanese Patent No. 2888972 JP-A-5-271478 JP-A-10-101879

  An object of the present invention is to provide a perfluoroelastomer composition that can provide a perfluororubber molded article having good processability, being difficult to scorch, and having excellent rubber properties and compression set properties. Another object of the present invention is to provide a perfluoroelastomer composition capable of providing a perfluororubber molded article having excellent tensile strength, tensile elongation at break and compression set, and a perfluoroelastomer obtained by crosslinking the composition. The object is to provide a fluororubber molded article. In this specification, a perfluoroelastomer composition is obtained by kneading various compounding agents such as a crosslinking agent with a perfluoroelastomer. A molded product obtained by crosslinking the composition is referred to as a perfluoro rubber molded product.

The present invention provides a perfluoroelastomer composition comprising (a) a perfluoroelastomer, (b) an organic peroxide, and (c) a scorch retarder.
In the perfluoroelastomer composition according to the present invention, the content of the component (b) is 0.05 to 10 parts by mass and the content of the component (c) is 0 per 100 parts by mass of the component (a). A perfluoroelastomer composition that is 0.01 to 5 parts by weight is provided.

In the perfluoroelastomer composition, the perfluoroelastomer as the component (a) is a repeating unit based on tetrafluoroethylene and CF ₂ ═CF—O—R ^f (wherein R ^f is an ether). A perfluoroelastomer composition which is a copolymer having a repeating unit based on a C 1-20 perfluoroalkyl group which may have an oxygen atom.
Moreover, this invention provides the perfluoroelastomer composition in which the perfluoroelastomer of (a) component contains an iodine atom and / or a bromine atom in the said perfluoroelastomer composition.

In addition, the present invention uses the Mooney viscosity of the perfluoroelastomer (a) component (a large rotor having a diameter of 38.1 mm and a thickness of 5.54 mm in accordance with JIS K6300) at 100 ° C. A perfluoroelastomer composition having a Mooney viscosity (measured with a preheating time of 1 minute and a rotor rotation time of 4 minutes) of 50 to 100 is provided.
Moreover, this invention provides the perfluoroelastomer composition whose 1 minute half-life temperature of the organic peroxide of (b) component is 150-250 degreeC in the said perfluoroelastomer composition.

In the perfluoroelastomer composition according to the present invention, the scorch retarder as the component (c) is at least one selected from the group consisting of phenolic hydroxyl group-containing compounds, quinones and α-methylstyrene dimers. A perfluoroelastomer composition is provided.
Further, the present invention is the above-mentioned perfluoroelastomer composition, wherein the perfluoroelastomer as the component (a) is a copolymer having a repeating unit based on tetrafluoroethylene and a repeating unit based on perfluoro (methyl vinyl ether). A perfluoroelastomer composition is provided.

  Further, the present invention provides the above-mentioned perfluoroelastomer composition, wherein the perfluoroelastomer as component (a) is a copolymer having a repeating unit based on tetrafluoroethylene and a repeating unit based on perfluoro (methyl vinyl ether). , (B) component organic peroxide is 2,5-dimethyl-2,5 (tert-butylperoxy) hexane, (c) component scorch retarder is o-phenylphenol, hydroquinone and 2, A perfluoroelastomer composition which is at least one selected from the group consisting of 4-diphenyl-4-methyl-1-pentene is provided.

The present invention further provides a perfluoroelastomer composition containing (d) sodium stearate in the perfluoroelastomer composition.
Moreover, this invention provides the perfluoroelastomer composition whose said (d) component is 0.1-10 mass parts per 100 mass parts of (a) component.
The present invention also provides a perfluororubber molded product obtained by thermally crosslinking the perfluoroelastomer composition described above.
Further, in the above perfluoro rubber molded article, the Mooney viscosity of the perfluoroelastomer of component (a) in the perfluoroelastomer composition is 30 or more, the perfluoroelastomer composition is thermally crosslinked perfluoro rubber tensile strength, measured in accordance with JIS K6251 of molded articles to provide a perfluoro rubber molded article is not less than 25 MPa.

  The perfluoroelastomer composition of the present invention has excellent crosslinkability, good processability, and is difficult to scorch. Moreover, the perfluoro rubber molded article of the present invention is excellent in plasma resistance, heat resistance and chemical resistance, and particularly excellent in compression set characteristics. Furthermore, the specific perfluoro rubber molded article of the present invention is excellent in tensile strength, tensile elongation at break, and compression set characteristics.

The perfluoroelastomer used in the perfluoroelastomer composition of the present invention includes a repeating unit based on ethylene tetrafluoride (hereinafter referred to as TFE) and CF ₂ ═CF—O—R ^f (wherein R ^f is an etheric compound). And a copolymer having a repeating unit based on a perfluoroalkyl group having 1 to 20 carbon atoms which may have an oxygen atom. CF ₂ ═CF—O—R ^f may be used alone or in combination of two or more. Preferred _{are, CF 2 = CF-O-} CF 3, CF 2 = CF-O-CF 2 CF 3, CF 2 = CF-O-CF 2 CF 2 CF 3, CF 2 = CF-O-CF 2 CF (CF ₃ ) OCF ₂ CF ₂ CF ₃ , CF ₂ ═CF—O—CF ₂ CF ₂ —O—CF ₂ CF _3, etc., more preferably CF ₂ ═CF—O—CF ₃ . Moreover, the preferable range of the carbon atom number of ^Rf is 1-20, and a more preferable range is 1-8.

The copolymerization ratio in the copolymer is preferably a repeating unit based on TFE / CF ₂ = repeating unit based on CF—O—R ^f = 30 to 80/70 to 20 (molar ratio). Within this range, the rubber properties are excellent.
As the perfluoroelastomer, it is preferable to use one that does not substantially contain a hydrogen atom, but it is also possible to use a perfluoroelastomer obtained by using a chain transfer agent or one containing a small amount of hydrogen atoms in a comonomer. it can. Examples of the chain transfer agent containing a hydrogen atom include chain or cyclic saturated hydrocarbons such as methane, ethane, propane, butane, pentane, hexane, and cyclohexane, alcohols such as methanol, ethanol, and propanol, tert-dodecyl mercaptan, Examples include mercaptans such as n-dodecyl mercaptan and n-octadecyl mercaptan. One or more chain transfer agents can be used.

As the comonomer containing a hydrogen _{atom, CF 2 = CF-O-} CH 2 CF 3, CF 2 = CF-O-CH 2 CF 2 CF 2 CF 3, CF 2 = CF-O-CH 2 (CF 2 _{CF 2) 2 H, CF 2} = CF-O-CF 2 CF 2 CH 2 -I, CF 2 = CF-O-CF 2 CF 2 CH 2 -Br, CF 2 = CF-O-CF 2 CF 2 ( _{CF 3) -O-CF 2 CF} 2 CH 2 -I, CF 2 = CF-O-CF 2 CF 2 (CF 3) such as _{-O-CF 2 CF 2 CH 2} -Br and can be exemplified. 1 type (s) or 2 or more types can be used for the comonomer containing a hydrogen atom. However, since the performance of perfluororubber such as heat resistance and chemical resistance deteriorates when the content of hydrogen atoms increases, the hydrogen atoms in the perfluoroelastomer used in the present invention is preferably 0.5% by mass or less. .3% by mass or less is more preferable, and 0.1% by mass or less is particularly preferable.

Furthermore, the perfluoroelastomer used in the present invention is preferably iodine and / or bromine-containing perfluoroelastomer, more preferably iodine-containing perfluoroelastomer. Examples of the iodine and / or bromine-containing perfluoroelastomer are described in JP-A-53-125491, JP-B-53-4115, and JP-A-59-20310. For example, in addition to at least one perfluoromonomer selected from the group consisting of TFE and CF ₂ ═CF—O—R ^f , polymerization may be performed using iodine and / or bromine-containing monomers, or I—R ^f2 —I (Wherein R ^f2 is a perfluoroalkylene group having 1 to 8 carbon atoms which may have an etheric oxygen atom), and obtained by copolymerizing the monomer in the presence of the compound represented by Perfluoroelastomers containing iodine and / or bromine can be used.

Examples of the iodine and / or bromine-containing monomer include CF ₂ ═CFBr, CH ₂ ═CHCF ₂ CF ₂ Br, CF ₂ ═CF—O—CF ₂ CF ₂ —I, and CF ₂ ═CF—O—CF ₂ CF _{2. -Br, CF 2 = CF-O} -CF 2 CF 2 CH 2 -I, CF 2 = CF-O-CF 2 CF 2 CH 2 -Br, CF 2 = CF-O-CF 2 CF 2 (CF 3) _{-O-CF 2 CF 2 CH 2} -I, CF 2 = CF-O-CF 2 CF 2 (CF 3) such as _{-O-CF 2 CF 2 CH 2} -Br and can be exemplified.
Specific examples of the I-R ^f2- I include diiododifluoromethane, 1,2-diiodoperfluoroethane, 1,3-diiodoperfluoropropane, 1,4-diiodoperfluorobutane, 1,5-diiodoperfluoropentane, 1,6-diiodoperfluorohexane, 1,7-diiodoperfluoroheptane, 1,8-diiodoperfluorooctane, and the like. 4-Diiodoperfluorobutane and 1,6-diiodoperfluorohexane are preferred, and 1,4-diiodoperfluorobutane is particularly preferred.

It is preferable that iodine and / or bromine in the perfluoroelastomer is bonded to the polymer terminal.
Although iodine content in the perfluoroelastomer used for this invention is not specifically limited, 0.1-1.5 mass% is preferable, 0.2-1.0 mass% is more preferable, 0.25-1.0 Mass% is particularly preferred. Within this range, a composition giving a crosslinked rubber having excellent rubber properties and compression set can be obtained.

Further, the Mooney viscosity at 100 ° C. according to JIS K6300 of the perfluoroelastomer used in the present invention is preferably 1 to 100, more preferably 5 to 50, and 5 to 30 in order to improve the blending operation. More preferably, 5 or more and less than 20 is particularly preferable. Moreover, in order to make it excellent in tensile strength, elongation at break, and compression set, the Mooney viscosity is preferably 30 or more, more preferably 40 to 100, and particularly preferably 50 to 100. Mooney viscosity is a measure of various average molecular weights, and a large molecular weight indicates a high molecular weight, and a small molecular weight indicates a low molecular weight. If the Mooney viscosity is high, the blending operation tends to be difficult, but if it is within this range, blending is easy and rubber properties after crosslinking are good.
The glass transition temperature (hereinafter referred to as Tg) of the perfluoroelastomer used in the present invention is preferably -50 to 25 ° C, more preferably -50 to 0 ° C, and most preferably -50 to -3 ° C.

  The organic peroxide (b), which is a crosslinking agent used in the present invention, is not particularly limited, but an organic peroxide having a 1 minute half-life temperature of 150 to 250 ° C., which is a temperature at which half of the organic peroxide decomposes in 1 minute. An oxide is preferable, and 150 to 200 ° C. is more preferable. Specific examples include ditert-butyl peroxide, tert-butylcumyl peroxide, dicumyl peroxide, α, α-bis (tert-butylperoxy) -p-diisopropylbenzene, 2,5-dimethyl-2, Dialkyl peroxides such as 5-di (tert-butylperoxy) hexane and 2,5-dimethyl-2,5-di (tert-butylperoxy) hexane-3, 1,1-di (tert-butylperoxy) Oxy) -3,3,5-trimethylcyclohexane, 2,5-dimethylhexane-2,5-dihydroxyperoxide, benzoyl peroxide, tert-butylperoxybenzene, 2,5-dimethyl-2,5-di (Benzoylperoxy) hexane, tert-butylperoxymaleic acid, tert-butylpero Examples thereof include xylisopropyl carbonate. 1 type (s) or 2 or more types can be used for an organic peroxide (b).

The content of the organic peroxide (b) is preferably 0.05 to 10 parts by mass, more preferably 0.3 to 5 parts by mass, and 0.5 to 3 parts by mass with respect to 100 parts by mass of the perfluoroelastomer. Part is most preferred. Within this range, a composition giving a crosslinked rubber having excellent rubber properties and compression set can be obtained.

  As the scorch retarder (c), bisphenol A, bisphenol AF, phenol, cresol, p-phenylphenol, m-phenylphenol, o-phenylphenol, allylphenol, p-hydroxybenzoic acid, ethyl p-hydroxybenzoate, etc. Phenolic hydroxyl group-containing compounds, quinones such as hydroquinone, hydroquinone monoethyl ether, hydroquinone monomethyl ether, 2,4-di (3-isopropylphenyl) -4-methyl-1-pentene, 2,4-di (4 -Isopropylphenyl) -4-methyl-1-pentene, 2- (3-isopropylphenyl) -4- (4-isopropylphenyl) -4-methyl-1-pentene, 2- (4-isopropylphenyl) -4- (3-Isopropylphenyl) -4-methyl 1-pentene, 2,4-di (3-methylphenyl) -4-methyl-1-pentene, 2,4-di (4-methylphenyl) -4-methyl-1-pentene, 2,4- Examples thereof include α-methylstyrene dimers such as diphenyl-4-methyl-1-pentene.

The scorch retarder (c) is preferably at least one selected from the group consisting of phenolic hydroxyl group-containing compounds, quinones and α-methylstyrene dimers.
The scorch retarder (c) is more preferably at least one selected from the group consisting of o-phenylphenol, hydroquinone and 2,4-diphenyl-4-methyl-1-pentene.

As the scorch retarder (c), o-phenylphenol or 2,4-diphenyl-4-methyl-1-pentene is more preferred, and o-phenylphenol is particularly preferred. The scorch retarder (c) can be used alone or in combination of two or more.
The content of the scorch retarder (c) is preferably 0.05 to 3 parts by mass and more preferably 0.05 to 1 part by mass with respect to 100 parts by mass of the perfluoroelastomer.

When crosslinking the perfluoroelastomer composition of the present invention, it is preferable to contain a crosslinking aid. When a crosslinking aid is contained, crosslinking efficiency is high. Specific examples of the crosslinking aid include triallyl cyanurate, triallyl isocyanurate, trimethallyl isocyanurate, 1,3,5-triacryloylhexahydro-1,3,5-triazine, triallyl trimellitate, m -Phenylenediamine bismaleimide, p-quinone dioxime, p, p'-dibenzoylquinone dioxime, dipropargyl terephthalate, diallyl phthalate, N, N ', N ", N""-tetraallyl terephthalamide, Examples thereof include vinyl group-containing siloxane oligomers such as polymethylvinylsiloxane and polymethylphenylvinylsiloxane. In particular, triallyl cyanurate, triallyl isocyanurate, and trimethallyl isocyanurate are preferable, and triallyl isocyanurate is more preferable. 0.1-10 mass parts is preferable with respect to 100 mass parts of perfluoroelastomers, and, as for content of a crosslinking adjuvant, 0.5-5 mass parts is more preferable. Within this range, crosslinked physical properties with a balance between strength and elongation can be obtained.
When the perfluoroelastomer composition of the present invention contains (d) sodium stearate, the perfluoroelastomer composition can maintain excellent physical properties such as tensile strength and elongation at break, and can have extremely low compression set. The content of the sodium stearate as the component (d) is preferably 0.1 to 10 parts by mass, more preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the perfluoroelastomer. Most preferred is 3 parts by weight.

  Furthermore, when the perfluoroelastomer composition of the present invention is cross-linked, a metal oxide may be contained as necessary. In particular, when the perfluoroelastomer is a bromine-containing perfluoroelastomer, the cross-linking reaction can be advanced promptly and reliably by containing a metal oxide. As specific examples of the metal oxide, oxides of divalent metals such as magnesium oxide, calcium oxide, zinc oxide and lead oxide are preferable. 0.1-10 mass parts is preferable with respect to 100 mass parts of perfluoroelastomer, and, as for content of a metal oxide, 0.5-5 mass parts is more preferable. Within this range, a crosslinked rubber molded article having excellent rubber properties and compression set characteristics can be obtained.

  Furthermore, when cross-linking the perfluoroelastomer composition of the present invention, pigments, fillers, reinforcing agents and the like for coloring may be contained. Commonly used pigments, fillers or reinforcing agents include carbon black, titanium oxide, silicon dioxide, clay, talc, polytetrafluoroethylene, polyvinylidene fluoride, polyvinyl fluoride, polychlorotrifluoroethylene, tetrafluoride Examples thereof include an ethylene / ethylene copolymer, an ethylene tetrafluoride / propylene copolymer, and an ethylene tetrafluoride / vinylidene fluoride copolymer. The content of the pigment is preferably 0.1 to 50 parts by mass with respect to 100 parts by mass of the perfluoroelastomer. The content of the filler is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the perfluoroelastomer. The content of the reinforcing agent is preferably 1 to 100 parts by mass with respect to 100 parts by mass of the perfluoroelastomer.

  The perfluoroelastomer composition of the present invention can be obtained by mixing the above components. Various mixing methods can be applied as the mixing method, but they may be kneaded with a two-roll, kneader, Banbury mixer or the like. If the heat generation is intense during kneading, it is preferable to cool a kneading machine such as a roll. The kneading temperature is preferably 60 ° C. or lower, and more preferably 50 ° C. or lower. The lower limit of the kneading temperature is not particularly limited, but is usually 20 ° C. or higher.

The perfluororubber molded article of the present invention is obtained by crosslinking and molding a perfluoroelastomer composition comprising (a) perfluoroelastomer, (b) organic peroxide and (c) scorch retarder as essential components. It is done.
Also, perfluoro rubber molded article of the present invention, (a) a Mooney viscosity of 30 or more perfluoroelastomer, perfluoroelastomer compositions containing as (b) an organic peroxide and (c) the scorch retarder as essential components The tensile strength measured according to JIS K6251 can be 25 MPa or more, preferably 27 MPa or more .

Molding may be performed simultaneously with crosslinking or may be performed before crosslinking. The molding method is not particularly limited, and examples thereof include various molding methods such as pressure molding, compression molding, extrusion molding, and injection molding.
The crosslinking reaction is preferably performed at 150 to 300 ° C. When crosslinked in this temperature range, a perfluoro rubber molded article having excellent rubber properties and compression set characteristics can be obtained. The crosslinking reaction is usually performed by combining a primary crosslinking reaction at a relatively low temperature and a secondary crosslinking reaction at a relatively high temperature.

The primary crosslinking reaction temperature is usually preferably 150 to 200 ° C. The secondary crosslinking reaction temperature is usually preferably 200 to 300 ° C, more preferably 220 to 290 ° C, and particularly preferably 230 to 280 ° C. What is necessary is just to select bridge | crosslinking time suitably. As a specific example of the combination of the primary crosslinking reaction and the secondary crosslinking reaction, for example, the primary crosslinking is performed for 3 to 60 minutes with a hot press at 150 to 200 ° C., and then for 2 to 24 hours in an oven at 200 to 300 ° C. It is preferable to perform secondary crosslinking.

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these.
The following methods were used to measure Mooney viscosity and physical properties.
[Mooney Viscosity] Viscosity measured according to JIS K6300 using a large rotor with a diameter of 38.1 mm and a thickness of 5.54 mm at 100 ° C. with a preheating time of 1 minute and a rotor rotation time of 4 minutes. Indicates. Larger values indicate higher molecular weight indirectly.
[Measurement of physical properties] A 2 mm thick crosslinked rubber sheet was punched out with a No. 3 dumbbell, and the tensile strength and elongation at break were measured according to JIS K6251. Further, the hardness was measured according to JIS K6253.

[Compression set] Measured according to JIS K6301.
Using the scorch Evaluation] Alpha Technologies Inc. Rubber process tester RPA2000, 12 minutes at 177 ° C., reaches 90% of the maximum torque shown in _{t 90} (bridge test at the time of performing cross tests at an angle 3 ° Until the scorch property was evaluated. scorch occurs if t ₉₀ is less than 1 minute, was that no scorch occurs if more than one minute. short time with t ₉₀ is small rubber composition after setting in a mold of the press until the crosslinking starts, poor operability at the time of processing.

[Example 1]
Repeating unit based on TFE / PMVE-based repeating unit obtained by copolymerizing TFE and perfluoro (methyl vinyl ether) (hereinafter referred to as PMVE) by emulsion polymerization in the presence of 1,4-diiodo-perfluorobutane = 100 parts by mass of 65/35 (molar ratio) perfluoroelastomer (Mooney viscosity 19.9, Tg = −5.0 ° C., iodine content = 0.52% by mass), 20% of carbon black as a reinforcing agent Parts, 3 parts by mass of triallyl isocyanurate (hereinafter referred to as TAIC) as a crosslinking aid, 2,5-dimethyl-2,5 (tert-butylperoxy) hexane (manufactured by NOF Corporation, 1 part by mass of trade name "Perhexa 25B") and 0.3 part by mass of o-phenylphenol as a scorch retarder in two rolls By kneading, a total of 124.3 parts by mass of a perfluoroelastomer composition was obtained. The scorch property of the composition was evaluated. Further, this perfluoroelastomer composition was subjected to primary crosslinking by hot pressing at 170 ° C. for 20 minutes, and then secondary crosslinked at 250 ° C. for 4 hours to obtain a crosslinked rubber sheet having a thickness of 2 mm. The physical properties and compression set of this rubber sheet were measured. The results are shown in Table 1.

[Example 2]
The perfluoroelastomer composition obtained in Example 1 was subjected to primary crosslinking by hot pressing at 170 ° C. for 20 minutes and then secondary crosslinked at 200 ° C. for 4 hours to obtain a crosslinked rubber sheet having a thickness of 2 mm. The physical properties and compression set of this rubber sheet were measured. The results are shown in Table 1.

[Example 3]
A perfluoroelastomer composition was obtained in the same manner as in Example 1 except that 0.5 part by mass of hydroquinone was used as the scorch retarder. The scorch property of the composition was evaluated. Further, a crosslinked rubber sheet having a thickness of 2 mm was obtained from the composition in the same manner as in Example 1. The physical properties and compression set of this rubber sheet were measured. The results are shown in Table 1.

[Example 4]
Perfluorocarbon was used in the same manner as in Example 1 except that 0.15 parts by mass of 2,4-diphenyl-4-methyl-1-pentene (trade name “NOFMER MSD” manufactured by NOF Corporation) was used as the scorch retarder. An elastomer composition was obtained. The scorch property of the composition was evaluated. Further, a crosslinked rubber sheet having a thickness of 2 mm was obtained from the composition in the same manner as in Example 1. The physical properties and compression set of this rubber sheet were measured. The results are shown in Table 1.

[Example 5]
Repeating unit based on TFE / PMVE-based repeating unit obtained by copolymerizing TFE and perfluoro (methyl vinyl ether) (hereinafter referred to as PMVE) by emulsion polymerization in the presence of 1,4-diiodo-perfluorobutane = 100 parts by mass of 65/35 (molar ratio) perfluoroelastomer (Mooney viscosity 59.3, Tg = −5.0 ° C., iodine content = 0.36% by mass), 20% of carbon black as a reinforcing agent Parts, 3 parts by mass of triallyl isocyanurate (hereinafter referred to as TAIC) as a crosslinking aid, 2,5-dimethyl-2,5 (tert-butylperoxy) hexane (manufactured by NOF Corporation, 1 part by mass of trade name “Perhexa 25B”) and 0.2 part by mass of o-phenylphenol as a scorch retarder in two rolls By kneading, a total of 124.2 parts by mass of a perfluoroelastomer composition was obtained. This perfluoroelastomer composition was subjected to primary crosslinking by hot pressing at 170 ° C. for 20 minutes, and then secondary crosslinked at 250 ° C. for 4 hours to obtain a crosslinked rubber sheet having a thickness of 2 mm. The physical properties and compression set of this rubber sheet were measured. The results are shown in Table 1.
The cross-linked perfluoro rubber obtained in Examples 1 to 5 was excellent in plasma resistance, chemical resistance, and heat resistance.

[Example 6]
Repeating unit based on TFE / PMVE-based repeating unit obtained by copolymerizing TFE and perfluoro (methyl vinyl ether) (hereinafter referred to as PMVE) by emulsion polymerization in the presence of 1,4-diiodo-perfluorobutane = 100 parts by mass of 65/35 (molar ratio) perfluoroelastomer (Mooney viscosity 19.9, Tg = −5.0 ° C., iodine content = 0.52% by mass), 20% of carbon black as a reinforcing agent Parts, 3 parts by mass of triallyl isocyanurate (hereinafter referred to as TAIC) as a crosslinking aid, 2,5-dimethyl-2,5 (tert-butylperoxy) hexane (manufactured by NOF Corporation, 1 part by mass of trade name “Perhexa 25B”), 0.3 part by mass of o-phenylphenol as a scorch retarder, stearic acid One part by mass of sodium was kneaded with two rolls to obtain a total of 125.3 parts by mass of a perfluoroelastomer composition. The scorch property of the composition was evaluated. Further, this perfluoroelastomer composition was subjected to primary crosslinking by hot pressing at 170 ° C. for 20 minutes, and then secondary crosslinked at 250 ° C. for 4 hours to obtain a crosslinked rubber sheet having a thickness of 2 mm. The physical properties and compression set of this rubber sheet were measured. The results are shown in Table 1.

[Comparative Example 1]
A perfluoroelastomer composition was obtained in the same manner as in Example 1 except that no scorch retarder was used. The scorch property of the composition was evaluated. Further, a crosslinked rubber sheet having a thickness of 2 mm was obtained from the composition in the same manner as in Example 1. The physical properties and compression set of this rubber sheet were measured. The results are shown in Table 1.

  The perfluoroelastomer composition and the perfluororubber molded product of the present invention are used for O-rings, sheets, gaskets, oil seals, diaphragms, and V-rings. Moreover, it can be applied to applications such as semiconductor device sealing materials, chemical-resistant sealing materials, paints, and wire coating materials.

Claims (13)

  A perfluoroelastomer composition comprising (a) perfluoroelastomer, (b) an organic peroxide, and (c) a scorch retarder.   The par according to claim 1, wherein the content of the component (b) is 0.05 to 10 parts by mass and the content of the component (c) is 0.01 to 5 parts by mass per 100 parts by mass of the component (a). Fluoroelastomer composition. The perfluoroelastomer as the component (a) is a repeating unit based on ethylene tetrafluoride and CF ₂ = CF—O—R ^f (wherein R ^f has 1 carbon atom which may have an etheric oxygen atom) The perfluoroelastomer composition according to claim 1, which is a copolymer having a repeating unit based on ˜20 perfluoroalkyl groups.   The perfluoroelastomer composition according to any one of claims 1 to 3, wherein the (a) component perfluoroelastomer contains an iodine atom and / or a bromine atom.   Mooney viscosity of component (a) perfluoroelastomer (according to JIS K6300, using a large rotor with a diameter of 38.1 mm and a thickness of 5.54 mm, at 100 ° C., preheating time 1 minute, rotor rotation time 4 minutes The perfluoroelastomer composition according to any one of claims 1 to 4, wherein the Mooney viscosity (measured by setting to 2) is 50 to 100. The perfluoroelastomer composition according to any one of claims 1 to 5, wherein the organic peroxide as the component (b) has a one-minute half-life temperature of 150 to 250 ° C. (C) component of the scorch retarder, a phenolic hydroxyl group-containing compounds, perfluoro according to claim 1 is at least one selected from the group consisting of quinones and α- methylstyrene dimers Elastomer composition. The perfluoroelastomer according to any one of claims 1 to 7 , wherein the perfluoroelastomer as the component (a) is a copolymer having a repeating unit based on tetrafluoroethylene and a repeating unit based on perfluoro (methyl vinyl ether). Composition.   The component (a) perfluoroelastomer is a copolymer having a repeating unit based on ethylene tetrafluoride and a repeating unit based on perfluoro (methyl vinyl ether), and the organic peroxide as the component (b) is 2,5. -Dimethyl-2,5 (tert-butylperoxy) hexane, wherein the scorch retarder of component (c) is composed of o-phenylphenol, hydroquinone and 2,4-diphenyl-4-methyl-1-pentene The perfluoroelastomer composition according to claim 1, which is at least one selected from the group consisting of:   The perfluoroelastomer composition according to any one of claims 1 to 9, further comprising (d) sodium stearate.   The perfluoroelastomer composition according to claim 10, wherein the content of the component (d) is 0.1 to 10 parts by mass per 100 parts by mass of the component (a).   A perfluororubber molded product obtained by thermally crosslinking the perfluoroelastomer composition according to claim 1.   Tensile strength measured according to JIS K6251 of a perfluoro rubber molded product in which the perfluoroelastomer of the component (a) in the perfluoroelastomer composition has a Mooney viscosity of 30 or more and the perfluoroelastomer composition is thermally crosslinked. The perfluoro rubber molded article according to claim 12, which has a strength of 25 MPa or more.